Retroactivity

The assumption that is usually made when designing or analyzing a network modularly is that the input/output behavior of a module does not change upon interconnection. We have discovered that, just as in many electrical, mechanical, and hydraulic systems, this assumption is not satisfied in biomolecular systems. Specifically, upon interconnection of a biomolecular component with a downstream system, “impedance-like” effects arise, which alter the behavior of the upstream component. We have called these effects retroactivity, to extend the notion of impedance to non- electrical circuits and in particular to biomolecular systems. We are developing a network theory based on retroactivity that seeks to determine retroactivity to the input and to the output of any general network. This Will allow to reliably predict the behavior of complex Interconnected networks from the behavior of their “modules”, Just like Thevenin’s theorem does in electrical circuits. We experimentally validate our hypothesis by constructing test Circuits in E coli to measure retroactivity